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3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6 

 

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Posted: Tue Dec 30, 2008 11:02 pm 
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tickford_6 wrote:

there is no set of diff gears that will all diffs EA to AU. there was a change over part way through the EF model run.


exactly what was changed?

isnt the housing the same still

 

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Posted: Wed Dec 31, 2008 3:37 pm 
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diff's that are 3.08 will not take anything higher ... ea had 2.77 and 2.92 and some ED's had 3.08. you need a 323.1 housing to fit them in ...

I learnt that at work!

 

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Posted: Wed Dec 31, 2008 4:13 pm 
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ive got a 3.45 housing so should be right then ay?

 

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Posted: Wed Dec 31, 2008 5:37 pm 
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the housing looks the same on the outside, but the machining is different on the inside.

you can machine or add spacers to the pinion to make it work. (so i'm told my malwood)

 

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Posted: Wed Dec 31, 2008 5:52 pm 
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Its well worth it.

The only thing it may induce is wheel spin, 3.9 is what I'd go.

 

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Posted: Wed Dec 31, 2008 6:50 pm 
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tickford_6 wrote:
the housing looks the same on the outside, but the machining is different on the inside.

you can machine or add spacers to the pinion to make it work. (so i'm told my malwood)

sweet at least i know if it doesnt work straight up theres a way around it!



schnoods wrote:
Its well worth it.

The only thing it may induce is wheel spin, 3.9 is what I'd go.


sweet, yeah im pretty excited. Im expecting a little more wheelspin ill just have to let some air out of the tyres at the strip maybe, Ive never had to in the past!

 

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14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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 Post subject: Re: 3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6
Posted: Fri Feb 20, 2009 1:11 am 
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gears are in! 3.89:1
its a bit of a shame though there is a bit of a whine to the diff now. its a good mate of mine who put them in, he said its one of 2 things (since the backlash and tooth reading were spot on) being second hand gears they could have some bad wear somewhere, or that when these gears were in the previous car they were run at a different tooth reading and it just takes time for the new tooth reading to wear in and for the noise to quiten down.
im gonna monitor it and see if it gets worse.

any thoughts or suggestions??

Also the new shocks are in monroe gt sport, they feel freakin sic, the car is niiice and stiff. definately recommend for 4-500 bux!

 

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El xr6
14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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 Post subject: Re: 3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6
Posted: Fri Feb 20, 2009 5:03 am 
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whining is an issue with almost all of the 2nd hand bw a***, most are from early model pintara's and skylines (re: r31 model), could be due to age i guess. maybe even design, could be why btr never went beyond the 3.45 ratio, as there may be an inherint noise issue with the way the higher ratio's teeth design needs to be. who knows.


my car has 3.89's in a 3.08 housing, rubish they dont fit. with the right bearing they fit fine. the only problem i have is that since lowering the car whine is worse and i get vibration on deceleration due to incorrect pinion angle, as lowering the rear has brought the back wheel slighlty forward altering the geometry. need xr trailing arms to rectify, as they push the whole diff setup towards the back of the car by about 20mm iirc.

just gotta get arund to it. fk im slack lol.

how do you find the gear separation with the 3.89's behind a t5? i imagine first would be non existant, and that effectively you now have a 4 speed manual that revs high on the long black.
I always thought if ever the au got a t5 (by some darkcraft) that a 3.23 would be adequate to tighten up the ratios. my brother had a t5 ef with standard 3.08 and first was short enough as it was.

 

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 Post subject: Re: 3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6
Posted: Fri Feb 20, 2009 5:06 am 
Getting Side Ways
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whining is an issue with almost all of the 2nd hand bw a***, most are from early model pintara's and skylines (re: r31 model), could be due to age i guess. maybe even design, could be why btr never went beyond the 3.45 ratio, as there may be an inherint noise issue with the way the higher ratio's teeth design needs to be. who knows.


my car has 3.89's in a 3.08 housing, rubish they dont fit. with the right bearing they fit fine. the only problem i have is that since lowering the car whine is worse and i get vibration on deceleration due to incorrect pinion angle, as lowering the rear has brought the back wheel slighlty forward altering the geometry. need xr trailing arms to rectify, as they push the whole diff setup towards the back of the car by about 20mm iirc.

just gotta get arund to it. fk im slack lol.

how do you find the gear separation with the 3.89's behind a t5? i imagine first would be non existant, and that effectively you now have a 4 speed manual that revs high on the long black.
I always thought if ever the au got a t5 (by some darkcraft) that a 3.23 would be adequate to tighten up the ratios. my brother had a t5 ef with standard 3.08 and first was short enough as it was.

 

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 Post subject: Re: 3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6
Posted: Fri Feb 20, 2009 9:01 am 
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Grimketel wrote:
whining is an issue with almost all of the 2nd hand bw a***, most are from early model pintara's and skylines (re: r31 model), could be due to age i guess. maybe even design, could be why btr never went beyond the 3.45 ratio, as there may be an inherint noise issue with the way the higher ratio's teeth design needs to be. who knows.


my car has 3.89's in a 3.08 housing, rubish they dont fit. with the right bearing they fit fine. the only problem i have is that since lowering the car whine is worse and i get vibration on deceleration due to incorrect pinion angle, as lowering the rear has brought the back wheel slighlty forward altering the geometry. need xr trailing arms to rectify, as they push the whole diff setup towards the back of the car by about 20mm iirc.

just gotta get arund to it. fk im slack lol.

how do you find the gear separation with the 3.89's behind a t5? i imagine first would be non existant, and that effectively you now have a 4 speed manual that revs high on the long black.
I always thought if ever the au got a t5 (by some darkcraft) that a 3.23 would be adequate to tighten up the ratios. my brother had a t5 ef with standard 3.08 and first was short enough as it was.


yeah that makes sense about the whole age thing. my dad had an r31 once and he said the diff was noisy as s**t in that too!
i had a vibration also when i put everything back in, mainly at around 100k's when i backed off. to fix this i just spun the tailshaft around 180 degrees to the opposite postion on the diff plate thing and the vibration completely went away!

its actually not all that bad! first is definately a heap shorter but can definately still be used, pretty much only when you are at a halt thought, rolling still at any speed its too easy for the car to just take off in 2nd.
1st gear still shoots the car up to just over 50k's really quick so its a fair starting speed!

 

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El xr6
14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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